Sheet post-processing unit and image forming apparatus

Abstract

A sheet post-processing unit usable in an image forming apparatus includes a sheet stacking device; a sheet conveying device including at least one roller rotatably supported by an arm movably and vertically rockingly supported, an actuator for moving the arm capable of selectively conveying each sheet to be discharged and of separating from the sheet by moving in a vertical direction; a control section for setting a moving distance of the intersectional moving device corresponding to a size of each sheet to be discharged; and a sheet clamping device. The roller abuts an uppermost sheet among sheets stacked on the sheet stacking device and an intersectional moving device moves the roller in the intersecting direction by a moving distance corresponding to the sheet size set by the control section to hit against and align the uppermost sheet with an upstream side regulating member and an intersectional regulating member.

1. A sheet post-processing unit, comprising:
 sheet stacking means for stacking sheets sequentially discharged one after another; 
 sheet conveying means including at least one roller rotatably supported by an arm movably and vertically rockingly supported along an axis, and an actuator for moving said arm in a vertical direction and capable of selectively conveying each sheet to be discharged in downstream and upstream directions of a sheet conveying direction and of separating from the sheet by moving in the vertical direction; 
 an upstream side regulating member for aligning each sheet stacked on said sheet stacking means by hitting against an upstream edge of the sheet; 
 intersectional moving means for moving said arm of said sheet conveying means in a direction intersecting with the sheet conveying direction along the axis; 
 an intersectional regulating member for aligning each sheet by hitting against an edge of the sheet on a side intersecting with the sheet conveying direction; 
 a control section for setting a moving distance of said intersectional moving means corresponding to a size of each sheet to be discharged on the basis of information relating to sizes of sheets sequentially discharged to said sheet stacking means; and 
 clamping means for clamping sheets to prevent the sheets from following a moving succeeding sheet when the succeeding sheet is stacked on the preceding sheet stacked on said sheet stacking means, 
 wherein said at least one roller of said sheet conveying means abuts an uppermost sheet among sheets stacked on said sheet stacking means and said intersectional moving means moves said at least one roller in the intersecting direction by the moving distance corresponding to the sheet size set by said control section to hit against and align the uppermost sheet with said upstream side regulating member and said intersectional regulating member. 
 
   
   
     2. The sheet post-processing unit as set forth in  claim 1 , further comprising post-processing means for post-processing sheets aligned by said upstream side regulating member and said intersectional regulating member. 
   
   
     3. The sheet post-processing unit as set forth in  claim 1 , wherein said control section sets each moving distance of the uppermost sheet conveyed by said at least one roller that aligns the sheet by hitting the edge of the sheet against said intersectional regulating member so that each moving distance is larger than a distance between an abutting edge of the uppermost sheet and said intersectional regulating member, and so that said at least one roller slides on the uppermost sheet after hitting against said intersectional regulating member. 
   
   
     4. The sheet post-processing unit as set forth in  claim 1 , wherein said control section (i) recognizes a plurality of sheets sequentially discharged to said sheet stacking means and whose sheet sizes are different at least in the intersectional direction, and (ii) moves said intersectional moving means by a moving distance corresponding to a size of a succeeding sheet, differing from a moving distance corresponding to a size of a preceding sheet, to hit and align the succeeding sheet to said intersectional regulating member when the size of the succeeding sheet is different from the size of the preceding sheet. 
   
   
     5. The sheet post-processing unit as set forth in  claim 1 , wherein said sheet stacking means includes a tray,
 wherein said at least one roller is contactable with/separable from each sheet stacked on said tray and is rotatable in a normal or reverse direction, and 
 wherein said intersectional moving means is a reciprocal driving device for moving said at least one roller in the direction intersecting with the sheet conveying direction. 
 
   
   
     6. The sheet post-processing unit as set forth in  claim 1 , wherein an outer periphery of said at least one roller is made of rubber or an elastic material similar to rubber, such as a foam material. 
   
   
     7. The sheet post-processing unit as set forth in  claim 1 , wherein said sheet stacking means is a first sheet stacking means, the sheet post-processing unit further comprising:
 second sheet stacking means, disposed in the vicinity of the first sheet stacking means, and movable in the vertical direction for stacking sheets; and 
 transfer means for holding and transferring sheets stacked on said first sheet stacking means to said second sheet stacking means. 
 
   
   
     8. The sheet post-processing unit as set forth in  claim 7 , further comprising:
 sheet bundle pressing means for pressing sheets stacked on said second sheet stacking means from the top; and 
 moving means for selectively moving said sheet bundle pressing means to a pressing position for pressing sheets stacked on said second sheet stacking means from the top and to an evacuation position under said first sheet stacking means, 
 wherein said transfer means includes sheet bundle discharging means for discharging a bundle of sheets on said first sheet stacking means onto said second sheet stacking means, and 
 wherein said moving means moves said sheet bundle pressing means to the pressing position after finishing an operation of said sheet bundle discharging means for discharging the bundle of sheets. 
 
   
   
     9. The sheet post-processing unit as set forth in  claim 8 , wherein said moving means moves said sheet bundle pressing means to the evacuation position in linkage with a movement of said sheet bundle discharging means in a sheet bundle discharging direction. 
   
   
     10. The sheet post-processing unit as set forth in  claim 8 , wherein said moving means includes a cam that turns along with movement of said sheet bundle discharging means. 
   
   
     11. The sheet post-processing unit as set forth in  claim 8 , wherein said sheet bundle discharging means includes sheet bundle clamping means for clamping the bundle of sheets on said first sheet stacking means and said sheet bundle clamping means releases the bundle of sheets after said sheet bundle discharging means arrives at a position for discharging the bundle of sheets. 
   
   
     12. The sheet post-processing unit as set forth in  claim 8 , further comprising:
 a sheet bundle Wailing edge hitting member, provided so as to be able to go in and out at an end of said first sheet stacking means on a side of said second sheet stacking means, for hitting against a trailing edge of the bundle of sheets; and 
 hitting member moving means for moving and projecting out said sheet bundle trailing edge hitting member from the end of said first sheet stacking means on the side of said second sheet stacking means, 
 wherein said transfer means is the sheet bundle discharging means for clamping and discharging the bundle of sheets on said first sheet stacking means to said second sheet stacking means, 
 wherein said sheet bundle discharging means releases the bundle of sheets after moving to a position for discharging the bundle of sheets, and 
 wherein said hitting member moving means projects out said sheet bundle trailing edge hitting member on an upstream side of said sheet bundle discharging means when said sheet bundle discharging means arrives at a position for discharging the bundle of sheets so that the trailing edge of the bundle of sheets which has been released from said sheet bundle discharging means hits against said sheet bundle trailing edge hitting member when said sheet bundle discharging means returns to a position before moving. 
 
   
   
     13. The sheet post-processing unit as set forth in  claim 12 , wherein said hitting member moving means includes a solenoid. 
   
   
     14. The sheet post-processing unit as set forth in  claim 12 , wherein said hitting member moving means includes a pressing member which moves in linkage with movement of said sheet bundle discharging means and presses said sheet bundle trailing edge hitting member in a projecting direction. 
   
   
     15. A sheet post-processing unit, comprising:
 first sheet stacking means for stacking sheets sequentially discharged one after another; 
 sheet conveying means including at least one roller rotatably supported by an arm movably and vertically rockingly supported along an axis, and an actuator for moving said arm in a vertical direction and capable of selectively conveying each sheet to be discharged to said first sheet stacking means in downstream and upstream directions of a sheet conveying direction and of separating from the sheet by moving in the vertical direction; 
 an upstream side regulating member for aligning each sheet stacked on said sheet stacking means by hitting against an upstream edge of the sheet; 
 intersectional moving means for moving said arm of said sheet conveying means in a direction intersecting with the sheet conveying direction along the axis; 
 an intersectional regulating member for aligning each sheet by hitting against an edge of the sheet on a side intersecting with the sheet conveying direction; 
 a control section for setting a moving distance of said intersectional moving means corresponding to a size each sheet to be discharged on the basis of information relating to sizes of sheets sequentially discharged to said sheet stacking means; 
 post-processing means for post-processing sheets aligned by said upstream side regulating member and said intersectional regulating means; 
 second sheet stacking means, disposed in the vicinity of said first sheet stacking means and movable in a vertical direction, for stacking sheets; and 
 transfer means for clamping and transferring sheets stacked on said first sheet stacking means to said second sheet stacking means, 
 wherein said at least one roller of said sheet conveying means abuts an uppermost sheet among sheets stacked on said first sheet stacking means and said intersectional moving means moves said at least one roller in the intersecting direction by the moving distance corresponding to a sheet size set by said control section to hit against and align the uppermost sheet with said upstream side regulating member and said intersectional regulating member, 
 wherein said post-processing means includes a stapling device for binding the aligned bundle of sheets, 
 wherein said second sheet stacking means includes a tray, and 
 wherein said transfer means includes a sheet bundle discharging member for discharging the bound bundle of sheets to said tray. 
 
   
   
     16. An image forming apparatus, comprising:
 image forming means for forming images; 
 sheet stacking means for stacking sheets sequentially discharged one after another; 
 sheet conveying means including at least one roller rotatably supported by an arm movably and vertically rockingly supported along an axis, and an actuator for moving said arm in a vertical direction and capable of selectively conveying each sheet to be discharged in downstream and upstream directions of a sheet conveying direction and of separating from the sheet by moving in the vertical direction; 
 an upstream side regulating member for aligning each sheet stacked on said sheet stacking means by hitting against an upstream edge of the sheets; 
 intersectional moving means for moving said arm of said sheet conveying means in a direction intersecting with the sheet conveying direction along the axis; 
 an intersectional regulating member for aligning each sheet by hitting against an edge of the sheet on a side intersecting with the sheet conveying direction; 
 a control section for setting a moving distance of said intersectional moving means corresponding to a size of each sheet to be discharged on the basis of information relating to sizes of sheets sequentially discharged to said sheet stacking means; and 
 clamping means for clamping sheets to prevent the sheets from following a moving succeeding sheet when the succeeding sheet is stacked on the preceding sheet stacked on said sheet stacking means, 
 wherein said at least one roller of said sheet conveying means abuts an uppermost sheet among sheets stacked on said sheet stacking means and said intersectional moving means moves said at least one roller in the intersecting direction by the moving distance corresponding to the sheet size set by said control section to hit against and align the uppermost sheet with said upstream side regulating member and said intersectional regulating member. 
 
   
   
     17. The image forming apparatus as set forth in  claim 16 , wherein said sheet stacking means is a first sheet stacking means, the image forming apparatus further comprising:
 second sheet stacking means, disposed in the vicinity of said first sheet stacking means and movable in the vertical direction, for stacking the sheets; and 
 sheet bundle discharging means for clamping and transferring sheets stacked on said first sheet stacking means to said second sheet stacking means, 
 said control section further setting a moving distance of said second sheet stacking means so that a height of an upper face of the sheets transferred to said second sheet stacking means becomes substantially equal to a height of a stacking face of said first sheet stacking means after transferring the sheets to said second sheet stacking means by controlling said sheet bundle discharging means. 
 
   
   
     18. The image forming apparatus as set forth in  claim 17 , further comprising:
 sheet bundle pressing means for pressing sheets stacked on said second sheet stacking means from the top; and 
 moving means for selectively moving said sheet bundle pressing means to a pressing position for pressing the sheets from the top and to an evacuation position under said first sheet stacking means, 
 wherein said moving means moves said sheet bundle pressing means to the pressing position after finishing a sheet bundle discharging operation of said sheet bundle discharging means. 
 
   
   
     19. The image forming apparatus as set forth in  claim 17 , further comprising:
 sheet bundle discharging means for clamping and discharging a bundle of sheets on said first sheet stacking means toward said second sheet stacking means to discharge the bundle of sheets onto said second sheet stacking means; 
 a sheet bundle trailing edge hitting member, provided so as to be able to go in and out at an end of said first sheet stacking means on a side of said second sheet stacking means, for hitting against a trailing edge of the bundle of sheets; and 
 hitting member moving means for projecting said sheet bundle trailing edge hitting member from an end of said first sheet stacking means on the side of said second sheet stacking means; and 
 a control section for controlling said sheet bundle discharging means so as to release the bundle of sheets after moving to a position for discharging the bundle of sheets and for controlling said hitting member moving means so as to project said sheet bundle trailing edge hitting member on an upstream side of said sheet bundle discharging means after said sheet bundle discharging means has moved to a position for discharging the bundle of sheets so that the trailing edge of the bundle of sheets released from sheet bundle discharging means hits against said sheet bundle trailing edge hitting member when said sheet bundle discharging means returns to a position before moving.